Powder detergent is usually less expensive than liquid detergent. If you're on a budget and don't want to spend too much, powder is probably the way to go.
Powder detergent has a longer shelf life and can be purchased in bulk, which will also save you money. Of course, discount liquid detergents are also available.
Powder detergent sometimes fails to properly disintegrate in the wash. This most often occurs where there is hard water.
If you find yourself with this problem switch to liquid.
Spot removal with powder detergent is difficult. Liquid detergent offers the ability to scrub away stains before tossing the soiled garment in the wash.